I'm not aware of anyone who has specifically mentioned using that plugin. AppThemes does not officially support third party plugins, so we cannot guarantee all plugins will be compatible with our themes. I believe a customer has mentioned some success with
this one, however again, it is not part of the official testing process so this is based on customer feedback.
The good news is that Facebook integration is already a planned for a future release of ClassiPress, so this may be in v3.1 due out next month.